1. Technical Field
The present invention relates to an optical image capturing lens system. More particularly, the present invention relates to a compact optical image capturing lens system applicable to electronic products and three-dimensional (3D) image applications thereof.
2. Description of Related Art
In recent years, with the popularity of mobile products with camera functionalities, the demand of miniaturized optical lens systems is increasing. The sensor of a conventional photographing camera is typically a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact optical lens systems have gradually evolved toward the field of higher megapixels, there is an increasing demand for compact optical lens systems featuring better image quality.
A conventional compact optical lens system employed in a portable electronic product mainly adopts a structure of two-element lens such as the one disclosed in U.S. Pat. No. 7,957,076 B2. The ability of the two-element lens system for correcting the aberration thereof cannot satisfy the requirement of the high-end optical lens system. Although other conventional optical lens systems with four-element lens structure such as the one disclosed in U.S. Pat. No. 8,089,704 B2. However, the compact size thereof is limited by the number of the lens elements, and the costs together with the assembly of the optical lens system are more complicated.
In order to obtain a high image quality and to keep size compact, an optical lens system with three-element lens structure is provided, such as U.S. Pat. No. 7,515,358. Since the optical lens system includes a first lens element with positive refractive power and a second lens element with negative refractive power, the optical lens system does not equip with a good telephoto functionality and the total track length cannot be reduced. Furthermore, the third lens element has positive refractive power, so that the principal point thereof cannot be positioned away from an image plane, and the back focal length thereof cannot be effectively reduced. Therefore, it is hard to apply to the compact electronic products.